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Thread: Teensy 4.0 RTC amperage

  1. #1
    Junior Member
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    Teensy 4.0 RTC amperage

    My Teensy 4.0 RTC draws 29 microAmps. That's with a 2032 coin cell attached to Vbat and Gnd and no other T4 connections. Is there some way to reduce the current? Can I remove a diode? I don't care if the coin cell powers the RTC when the Teensy is powered through Vin or USB.

  2. #2
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    Unanswered for some time now ... maybe you got a personal reply?
    Anyway in the same situation I am measuring 31 microAmps, pretty much like you and would also like to know if this is normal for a 4.0. And even when the Teensy 4.0 is powered (through USB) the RTC draws 6 uA. Seems also too much to me.
    Don't know if it is relevant, but my figures come form a UNI-T UT61E.

  3. #3
    Senior Member blackketter's Avatar
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    Looking at the datasheet for the RT1060 , the current consumption of the crystal oscillator is about 6.5uA (p.32) plus the RTC consumption of 20uA for the SVNS (p.26). So, 29uA sounds about right.

  4. #4
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    Thanks for helping me to find the relevant figures in the datasheet!

    BTW: I have to correct my measurement figures somewhat:

    1) With a longer measurement period I saw that current consumption is on average 29..30 uA. When my calculations are correct that would mean for a new CR2032 (235 mAh) a lifetime of about 8000 hours, almost a year. I don't think I will leave the Teensy unpowered for such a long time!

    (2) When I power-off the Teensy the 'charging' current is starting at about -0.25uA, but pretty soon going to zero.

    Regards, Rob.

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